1. Field of the Invention
The present invention relates to an apparatus for supporting a linear-induction motor used for propelling vehicles such as, for example, railway cars.
2. Description of the Prior Art
In a linear motor-propelled railroad train system whose track facility consists of rails upon which the train travels and a linear motor reaction plate, there are usually present some dimenstional errors in laying the rails and the reaction plate and their combined relative errors become large. In addition, these errors result in variations in the distance defined between the primary coil and the reaction plate of the linear motor. Furthermore, in order to keep the primary coil upon the bogie from contacting the reaction plate, there is provided a standard gap of approximately ten millimeters between them. In order to maintain this gap, accurate laying work and also frequent adjustments are required, making the system costly.
The gap of ten millimeters provided between the primary coil and the reaction plate is very large when compared to the gap of one or two millimeters formed between the armature and the stator of the rotary motor. The large gap reduces the efficiency of the linear motor.
In order to install the linear motor, a suitable structure is proposed in Japanese Unexamined Publication No. 64251/1987, which has a dedicated support wheel for rendering the gap small and constant. In this prior art system, the primary coil is supported by means of the gap-setting support wheel, which rolls along both sides of the reaction plate which is laid upon the ground. Although this construction is simple, there is a drawback that the support wheel is acted upon means of the attractive force of the linear motor and thus must be strong enough to withstand that force.